1. Field of the Invention
The invention relates generally to the field of devices for plugging apertures in panels or the like, and is particularly useful in plugging apertures in tanks or pipes or in the hulls of boats or other water-going vessels. The invention is particularly advantageous in plugging irregularly-shaped apertures which can not be plugged by conventional cylindrical or conically-shaped stoppers.
2. Description of the Prior Art
A number of devices have been designed to plug apertures, the best known of which is a conical stopper make of rubber or cork. Conventional stoppers of this shape are, however, not very useful if the aperture is a puncture made, for example, by a pin or a nail, or if it is irregular, as the conical stopper is not able to seal around the irregularities of the aperture.
In addition to a conical stopper, several other types of devices have been designed to plug apertures. One such device, disclosed in U.S. Pat. No. 3,540,420 issued to R. F. Shores on Apr. 7, 1970, comprises a device having a nipple that is elongated by a special tool, which elongation causes a reduction in the diameter of the nipple. When in the elongated condition, the nipple is inserted into the aperture. The nipple is then allowed to relax, which allows the diameter of the nipple to enlarge and seal the aperture. The utility of this device, however, is generally limited to a narrow range of aperture sizes, specifically the range between the diameter when the nipple is elongated and the diameter when it is relaxed. Furthermore, the device requires the use of the special tool to insert the device. Another device, disclosed in U.S. Pat. No. 4,329,132, issued to R. W. Melvoid et al on May 11, 1982, can be used in a wider range of aperture sizes, but requires substantially more complex insertion hardware. This device comprises a flexible, inelastic bag which is inserted into the aperture in a collapsed condition. A foamable material generated by the insertion hardware is injected into the bag to cause it to expand and seal the aperture. Neither device, however, is useful in sealing punctures, which require string-like devices such as disclosed in U.S. Pat. No. 3,282,320, issued to E. F. Klouza on Nov. 1, 1966, and U.S. Pat. No. 3,035,626, issued to T. W. Mullen on May 22, 1962.
It is evident, however, that all of these plugging devices are limited to sealing a relatively narrow range of sizes of apertures and at least some of them require special tooling or hardware to insert them and make them stay in the apertures after insertion. Furthermore, none of these are particularly useful in sealing very irregularly shaped apertures.